The goal of this contract is to provide support of National Toxicology Program (NTP) hazard identification activities targeted toward the prevention of diseases or adverse effects caused by environmental exposure to chemical or physical agents. This contract involes the prechronic and chronic studies of 5 chemicals by gavage and dermal routes including Pentabromodiphenyl oxide (DE-71);Indole-3-carbinol;Methyl styryl ketone;Pentaerythritol triacrylate;and Trimethylolpropane triacrylate. The 90-Day studies of Pentaerythritol triacrylate, Pentabromodiphenyl oxide and Indole-3-carbinol have been completed and reported. The 2-year studies for Pentaerythritol triacrylate and Indole-3 carbinol have been cancelled from this contract. The in-life portion of the 2-year Methyl styryl ketone and Trimethylolpropane triacrylate studies have been completed. Chronic 2 year studies on Pentabromodiphenyl oxide are ongoing in rats and mice. In the Pentabromodiphenyl oxide chronic rat study, rats have been treated in utero beginning on gestation day 6, continuing through the lactation period and will be continuously treated through puberty to adulthood. Dosing will continue until rats are two years of age at which time animals will be thoroughly examined for signs of carcinogenicity. Keywords Carcinogenicty;Toxicity;Wistar Han rats;Fisher rats;B6C3F1 mice;perinatal;triacrylates, flame retardants;Pentabromodiphenyl oxide;DE-71;Indole-3-carbinol;Methyl styryl ketone;Pentaerythritol triacrylate;and Trimethylolpropane triacrylate.